| /* |
| * Resizable virtual memory filesystem for Linux. |
| * |
| * Copyright (C) 2000 Linus Torvalds. |
| * 2000 Transmeta Corp. |
| * 2000-2001 Christoph Rohland |
| * 2000-2001 SAP AG |
| * 2002 Red Hat Inc. |
| * Copyright (C) 2002-2005 Hugh Dickins. |
| * Copyright (C) 2002-2005 VERITAS Software Corporation. |
| * Copyright (C) 2004 Andi Kleen, SuSE Labs |
| * |
| * Extended attribute support for tmpfs: |
| * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> |
| * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> |
| * |
| * tiny-shmem: |
| * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/init.h> |
| #include <linux/vfs.h> |
| #include <linux/mount.h> |
| #include <linux/pagemap.h> |
| #include <linux/file.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/swap.h> |
| |
| static struct vfsmount *shm_mnt; |
| |
| #ifdef CONFIG_SHMEM |
| /* |
| * This virtual memory filesystem is heavily based on the ramfs. It |
| * extends ramfs by the ability to use swap and honor resource limits |
| * which makes it a completely usable filesystem. |
| */ |
| |
| #include <linux/xattr.h> |
| #include <linux/exportfs.h> |
| #include <linux/posix_acl.h> |
| #include <linux/generic_acl.h> |
| #include <linux/mman.h> |
| #include <linux/string.h> |
| #include <linux/slab.h> |
| #include <linux/backing-dev.h> |
| #include <linux/shmem_fs.h> |
| #include <linux/writeback.h> |
| #include <linux/blkdev.h> |
| #include <linux/percpu_counter.h> |
| #include <linux/splice.h> |
| #include <linux/security.h> |
| #include <linux/swapops.h> |
| #include <linux/mempolicy.h> |
| #include <linux/namei.h> |
| #include <linux/ctype.h> |
| #include <linux/migrate.h> |
| #include <linux/highmem.h> |
| #include <linux/seq_file.h> |
| #include <linux/magic.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/pgtable.h> |
| |
| #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) |
| #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
| |
| /* Pretend that each entry is of this size in directory's i_size */ |
| #define BOGO_DIRENT_SIZE 20 |
| |
| struct shmem_xattr { |
| struct list_head list; /* anchored by shmem_inode_info->xattr_list */ |
| char *name; /* xattr name */ |
| size_t size; |
| char value[0]; |
| }; |
| |
| /* Flag allocation requirements to shmem_getpage */ |
| enum sgp_type { |
| SGP_READ, /* don't exceed i_size, don't allocate page */ |
| SGP_CACHE, /* don't exceed i_size, may allocate page */ |
| SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
| SGP_WRITE, /* may exceed i_size, may allocate page */ |
| }; |
| |
| #ifdef CONFIG_TMPFS |
| static unsigned long shmem_default_max_blocks(void) |
| { |
| return totalram_pages / 2; |
| } |
| |
| static unsigned long shmem_default_max_inodes(void) |
| { |
| return min(totalram_pages - totalhigh_pages, totalram_pages / 2); |
| } |
| #endif |
| |
| static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
| struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type); |
| |
| static inline int shmem_getpage(struct inode *inode, pgoff_t index, |
| struct page **pagep, enum sgp_type sgp, int *fault_type) |
| { |
| return shmem_getpage_gfp(inode, index, pagep, sgp, |
| mapping_gfp_mask(inode->i_mapping), fault_type); |
| } |
| |
| static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
| { |
| return sb->s_fs_info; |
| } |
| |
| /* |
| * shmem_file_setup pre-accounts the whole fixed size of a VM object, |
| * for shared memory and for shared anonymous (/dev/zero) mappings |
| * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), |
| * consistent with the pre-accounting of private mappings ... |
| */ |
| static inline int shmem_acct_size(unsigned long flags, loff_t size) |
| { |
| return (flags & VM_NORESERVE) ? |
| 0 : security_vm_enough_memory_kern(VM_ACCT(size)); |
| } |
| |
| static inline void shmem_unacct_size(unsigned long flags, loff_t size) |
| { |
| if (!(flags & VM_NORESERVE)) |
| vm_unacct_memory(VM_ACCT(size)); |
| } |
| |
| /* |
| * ... whereas tmpfs objects are accounted incrementally as |
| * pages are allocated, in order to allow huge sparse files. |
| * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, |
| * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. |
| */ |
| static inline int shmem_acct_block(unsigned long flags) |
| { |
| return (flags & VM_NORESERVE) ? |
| security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; |
| } |
| |
| static inline void shmem_unacct_blocks(unsigned long flags, long pages) |
| { |
| if (flags & VM_NORESERVE) |
| vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
| } |
| |
| static const struct super_operations shmem_ops; |
| static const struct address_space_operations shmem_aops; |
| static const struct file_operations shmem_file_operations; |
| static const struct inode_operations shmem_inode_operations; |
| static const struct inode_operations shmem_dir_inode_operations; |
| static const struct inode_operations shmem_special_inode_operations; |
| static const struct vm_operations_struct shmem_vm_ops; |
| |
| static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
| .ra_pages = 0, /* No readahead */ |
| .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
| }; |
| |
| static LIST_HEAD(shmem_swaplist); |
| static DEFINE_MUTEX(shmem_swaplist_mutex); |
| |
| static void shmem_free_blocks(struct inode *inode, long pages) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| if (sbinfo->max_blocks) { |
| percpu_counter_add(&sbinfo->used_blocks, -pages); |
| inode->i_blocks -= pages*BLOCKS_PER_PAGE; |
| } |
| } |
| |
| static int shmem_reserve_inode(struct super_block *sb) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| if (sbinfo->max_inodes) { |
| spin_lock(&sbinfo->stat_lock); |
| if (!sbinfo->free_inodes) { |
| spin_unlock(&sbinfo->stat_lock); |
| return -ENOSPC; |
| } |
| sbinfo->free_inodes--; |
| spin_unlock(&sbinfo->stat_lock); |
| } |
| return 0; |
| } |
| |
| static void shmem_free_inode(struct super_block *sb) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| if (sbinfo->max_inodes) { |
| spin_lock(&sbinfo->stat_lock); |
| sbinfo->free_inodes++; |
| spin_unlock(&sbinfo->stat_lock); |
| } |
| } |
| |
| /** |
| * shmem_recalc_inode - recalculate the block usage of an inode |
| * @inode: inode to recalc |
| * |
| * We have to calculate the free blocks since the mm can drop |
| * undirtied hole pages behind our back. |
| * |
| * But normally info->alloced == inode->i_mapping->nrpages + info->swapped |
| * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) |
| * |
| * It has to be called with the spinlock held. |
| */ |
| static void shmem_recalc_inode(struct inode *inode) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| long freed; |
| |
| freed = info->alloced - info->swapped - inode->i_mapping->nrpages; |
| if (freed > 0) { |
| info->alloced -= freed; |
| shmem_unacct_blocks(info->flags, freed); |
| shmem_free_blocks(inode, freed); |
| } |
| } |
| |
| static void shmem_put_swap(struct shmem_inode_info *info, pgoff_t index, |
| swp_entry_t swap) |
| { |
| if (index < SHMEM_NR_DIRECT) |
| info->i_direct[index] = swap; |
| } |
| |
| static swp_entry_t shmem_get_swap(struct shmem_inode_info *info, pgoff_t index) |
| { |
| return (index < SHMEM_NR_DIRECT) ? |
| info->i_direct[index] : (swp_entry_t){0}; |
| } |
| |
| void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
| { |
| struct address_space *mapping = inode->i_mapping; |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| pgoff_t end = (lend >> PAGE_CACHE_SHIFT); |
| pgoff_t index; |
| swp_entry_t swap; |
| |
| truncate_inode_pages_range(mapping, lstart, lend); |
| |
| if (end > SHMEM_NR_DIRECT) |
| end = SHMEM_NR_DIRECT; |
| |
| spin_lock(&info->lock); |
| for (index = start; index < end; index++) { |
| swap = shmem_get_swap(info, index); |
| if (swap.val) { |
| free_swap_and_cache(swap); |
| shmem_put_swap(info, index, (swp_entry_t){0}); |
| info->swapped--; |
| } |
| } |
| |
| if (mapping->nrpages) { |
| spin_unlock(&info->lock); |
| /* |
| * A page may have meanwhile sneaked in from swap. |
| */ |
| truncate_inode_pages_range(mapping, lstart, lend); |
| spin_lock(&info->lock); |
| } |
| |
| shmem_recalc_inode(inode); |
| spin_unlock(&info->lock); |
| |
| inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
| } |
| EXPORT_SYMBOL_GPL(shmem_truncate_range); |
| |
| static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
| { |
| struct inode *inode = dentry->d_inode; |
| int error; |
| |
| error = inode_change_ok(inode, attr); |
| if (error) |
| return error; |
| |
| if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
| loff_t oldsize = inode->i_size; |
| loff_t newsize = attr->ia_size; |
| struct page *page = NULL; |
| |
| if (newsize < oldsize) { |
| /* |
| * If truncating down to a partial page, then |
| * if that page is already allocated, hold it |
| * in memory until the truncation is over, so |
| * truncate_partial_page cannot miss it were |
| * it assigned to swap. |
| */ |
| if (newsize & (PAGE_CACHE_SIZE-1)) { |
| (void) shmem_getpage(inode, |
| newsize >> PAGE_CACHE_SHIFT, |
| &page, SGP_READ, NULL); |
| if (page) |
| unlock_page(page); |
| } |
| } |
| if (newsize != oldsize) { |
| i_size_write(inode, newsize); |
| inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
| } |
| if (newsize < oldsize) { |
| loff_t holebegin = round_up(newsize, PAGE_SIZE); |
| unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); |
| shmem_truncate_range(inode, newsize, (loff_t)-1); |
| /* unmap again to remove racily COWed private pages */ |
| unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); |
| } |
| if (page) |
| page_cache_release(page); |
| } |
| |
| setattr_copy(inode, attr); |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| if (attr->ia_valid & ATTR_MODE) |
| error = generic_acl_chmod(inode); |
| #endif |
| return error; |
| } |
| |
| static void shmem_evict_inode(struct inode *inode) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_xattr *xattr, *nxattr; |
| |
| if (inode->i_mapping->a_ops == &shmem_aops) { |
| shmem_unacct_size(info->flags, inode->i_size); |
| inode->i_size = 0; |
| shmem_truncate_range(inode, 0, (loff_t)-1); |
| if (!list_empty(&info->swaplist)) { |
| mutex_lock(&shmem_swaplist_mutex); |
| list_del_init(&info->swaplist); |
| mutex_unlock(&shmem_swaplist_mutex); |
| } |
| } |
| |
| list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) { |
| kfree(xattr->name); |
| kfree(xattr); |
| } |
| BUG_ON(inode->i_blocks); |
| shmem_free_inode(inode->i_sb); |
| end_writeback(inode); |
| } |
| |
| static int shmem_unuse_inode(struct shmem_inode_info *info, |
| swp_entry_t swap, struct page *page) |
| { |
| struct address_space *mapping = info->vfs_inode.i_mapping; |
| pgoff_t index; |
| int error; |
| |
| for (index = 0; index < SHMEM_NR_DIRECT; index++) |
| if (shmem_get_swap(info, index).val == swap.val) |
| goto found; |
| return 0; |
| found: |
| spin_lock(&info->lock); |
| if (shmem_get_swap(info, index).val != swap.val) { |
| spin_unlock(&info->lock); |
| return 0; |
| } |
| |
| /* |
| * Move _head_ to start search for next from here. |
| * But be careful: shmem_evict_inode checks list_empty without taking |
| * mutex, and there's an instant in list_move_tail when info->swaplist |
| * would appear empty, if it were the only one on shmem_swaplist. |
| */ |
| if (shmem_swaplist.next != &info->swaplist) |
| list_move_tail(&shmem_swaplist, &info->swaplist); |
| |
| /* |
| * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
| * but also to hold up shmem_evict_inode(): so inode cannot be freed |
| * beneath us (pagelock doesn't help until the page is in pagecache). |
| */ |
| error = add_to_page_cache_locked(page, mapping, index, GFP_NOWAIT); |
| /* which does mem_cgroup_uncharge_cache_page on error */ |
| |
| if (error != -ENOMEM) { |
| delete_from_swap_cache(page); |
| set_page_dirty(page); |
| shmem_put_swap(info, index, (swp_entry_t){0}); |
| info->swapped--; |
| swap_free(swap); |
| error = 1; /* not an error, but entry was found */ |
| } |
| spin_unlock(&info->lock); |
| return error; |
| } |
| |
| /* |
| * shmem_unuse() search for an eventually swapped out shmem page. |
| */ |
| int shmem_unuse(swp_entry_t swap, struct page *page) |
| { |
| struct list_head *this, *next; |
| struct shmem_inode_info *info; |
| int found = 0; |
| int error; |
| |
| /* |
| * Charge page using GFP_KERNEL while we can wait, before taking |
| * the shmem_swaplist_mutex which might hold up shmem_writepage(). |
| * Charged back to the user (not to caller) when swap account is used. |
| * add_to_page_cache() will be called with GFP_NOWAIT. |
| */ |
| error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); |
| if (error) |
| goto out; |
| /* |
| * Try to preload while we can wait, to not make a habit of |
| * draining atomic reserves; but don't latch on to this cpu, |
| * it's okay if sometimes we get rescheduled after this. |
| */ |
| error = radix_tree_preload(GFP_KERNEL); |
| if (error) |
| goto uncharge; |
| radix_tree_preload_end(); |
| |
| mutex_lock(&shmem_swaplist_mutex); |
| list_for_each_safe(this, next, &shmem_swaplist) { |
| info = list_entry(this, struct shmem_inode_info, swaplist); |
| if (!info->swapped) { |
| spin_lock(&info->lock); |
| if (!info->swapped) |
| list_del_init(&info->swaplist); |
| spin_unlock(&info->lock); |
| } |
| if (info->swapped) |
| found = shmem_unuse_inode(info, swap, page); |
| cond_resched(); |
| if (found) |
| break; |
| } |
| mutex_unlock(&shmem_swaplist_mutex); |
| |
| uncharge: |
| if (!found) |
| mem_cgroup_uncharge_cache_page(page); |
| if (found < 0) |
| error = found; |
| out: |
| unlock_page(page); |
| page_cache_release(page); |
| return error; |
| } |
| |
| /* |
| * Move the page from the page cache to the swap cache. |
| */ |
| static int shmem_writepage(struct page *page, struct writeback_control *wbc) |
| { |
| struct shmem_inode_info *info; |
| swp_entry_t swap, oswap; |
| struct address_space *mapping; |
| pgoff_t index; |
| struct inode *inode; |
| |
| BUG_ON(!PageLocked(page)); |
| mapping = page->mapping; |
| index = page->index; |
| inode = mapping->host; |
| info = SHMEM_I(inode); |
| if (info->flags & VM_LOCKED) |
| goto redirty; |
| if (!total_swap_pages) |
| goto redirty; |
| |
| /* |
| * shmem_backing_dev_info's capabilities prevent regular writeback or |
| * sync from ever calling shmem_writepage; but a stacking filesystem |
| * might use ->writepage of its underlying filesystem, in which case |
| * tmpfs should write out to swap only in response to memory pressure, |
| * and not for the writeback threads or sync. |
| */ |
| if (!wbc->for_reclaim) { |
| WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ |
| goto redirty; |
| } |
| |
| /* |
| * Just for this patch, we have a toy implementation, |
| * which can swap out only the first SHMEM_NR_DIRECT pages: |
| * for simple demonstration of where we need to think about swap. |
| */ |
| if (index >= SHMEM_NR_DIRECT) |
| goto redirty; |
| |
| swap = get_swap_page(); |
| if (!swap.val) |
| goto redirty; |
| |
| /* |
| * Add inode to shmem_unuse()'s list of swapped-out inodes, |
| * if it's not already there. Do it now because we cannot take |
| * mutex while holding spinlock, and must do so before the page |
| * is moved to swap cache, when its pagelock no longer protects |
| * the inode from eviction. But don't unlock the mutex until |
| * we've taken the spinlock, because shmem_unuse_inode() will |
| * prune a !swapped inode from the swaplist under both locks. |
| */ |
| mutex_lock(&shmem_swaplist_mutex); |
| if (list_empty(&info->swaplist)) |
| list_add_tail(&info->swaplist, &shmem_swaplist); |
| |
| spin_lock(&info->lock); |
| mutex_unlock(&shmem_swaplist_mutex); |
| |
| oswap = shmem_get_swap(info, index); |
| if (oswap.val) { |
| WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ |
| free_swap_and_cache(oswap); |
| shmem_put_swap(info, index, (swp_entry_t){0}); |
| info->swapped--; |
| } |
| shmem_recalc_inode(inode); |
| |
| if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
| delete_from_page_cache(page); |
| shmem_put_swap(info, index, swap); |
| info->swapped++; |
| swap_shmem_alloc(swap); |
| spin_unlock(&info->lock); |
| BUG_ON(page_mapped(page)); |
| swap_writepage(page, wbc); |
| return 0; |
| } |
| |
| spin_unlock(&info->lock); |
| swapcache_free(swap, NULL); |
| redirty: |
| set_page_dirty(page); |
| if (wbc->for_reclaim) |
| return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ |
| unlock_page(page); |
| return 0; |
| } |
| |
| #ifdef CONFIG_NUMA |
| #ifdef CONFIG_TMPFS |
| static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
| { |
| char buffer[64]; |
| |
| if (!mpol || mpol->mode == MPOL_DEFAULT) |
| return; /* show nothing */ |
| |
| mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
| |
| seq_printf(seq, ",mpol=%s", buffer); |
| } |
| |
| static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) |
| { |
| struct mempolicy *mpol = NULL; |
| if (sbinfo->mpol) { |
| spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ |
| mpol = sbinfo->mpol; |
| mpol_get(mpol); |
| spin_unlock(&sbinfo->stat_lock); |
| } |
| return mpol; |
| } |
| #endif /* CONFIG_TMPFS */ |
| |
| static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| struct mempolicy mpol, *spol; |
| struct vm_area_struct pvma; |
| |
| spol = mpol_cond_copy(&mpol, |
| mpol_shared_policy_lookup(&info->policy, index)); |
| |
| /* Create a pseudo vma that just contains the policy */ |
| pvma.vm_start = 0; |
| pvma.vm_pgoff = index; |
| pvma.vm_ops = NULL; |
| pvma.vm_policy = spol; |
| return swapin_readahead(swap, gfp, &pvma, 0); |
| } |
| |
| static struct page *shmem_alloc_page(gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| struct vm_area_struct pvma; |
| |
| /* Create a pseudo vma that just contains the policy */ |
| pvma.vm_start = 0; |
| pvma.vm_pgoff = index; |
| pvma.vm_ops = NULL; |
| pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
| |
| /* |
| * alloc_page_vma() will drop the shared policy reference |
| */ |
| return alloc_page_vma(gfp, &pvma, 0); |
| } |
| #else /* !CONFIG_NUMA */ |
| #ifdef CONFIG_TMPFS |
| static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
| { |
| } |
| #endif /* CONFIG_TMPFS */ |
| |
| static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| return swapin_readahead(swap, gfp, NULL, 0); |
| } |
| |
| static inline struct page *shmem_alloc_page(gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| return alloc_page(gfp); |
| } |
| #endif /* CONFIG_NUMA */ |
| |
| #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
| static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) |
| { |
| return NULL; |
| } |
| #endif |
| |
| /* |
| * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
| * |
| * If we allocate a new one we do not mark it dirty. That's up to the |
| * vm. If we swap it in we mark it dirty since we also free the swap |
| * entry since a page cannot live in both the swap and page cache |
| */ |
| static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
| struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) |
| { |
| struct address_space *mapping = inode->i_mapping; |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_sb_info *sbinfo; |
| struct page *page; |
| struct page *prealloc_page = NULL; |
| swp_entry_t swap; |
| int error; |
| |
| if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) |
| return -EFBIG; |
| repeat: |
| page = find_lock_page(mapping, index); |
| if (page) { |
| /* |
| * Once we can get the page lock, it must be uptodate: |
| * if there were an error in reading back from swap, |
| * the page would not be inserted into the filecache. |
| */ |
| BUG_ON(!PageUptodate(page)); |
| goto done; |
| } |
| |
| /* |
| * Try to preload while we can wait, to not make a habit of |
| * draining atomic reserves; but don't latch on to this cpu. |
| */ |
| error = radix_tree_preload(gfp & GFP_RECLAIM_MASK); |
| if (error) |
| goto out; |
| radix_tree_preload_end(); |
| |
| if (sgp != SGP_READ && !prealloc_page) { |
| prealloc_page = shmem_alloc_page(gfp, info, index); |
| if (prealloc_page) { |
| SetPageSwapBacked(prealloc_page); |
| if (mem_cgroup_cache_charge(prealloc_page, |
| current->mm, GFP_KERNEL)) { |
| page_cache_release(prealloc_page); |
| prealloc_page = NULL; |
| } |
| } |
| } |
| |
| spin_lock(&info->lock); |
| shmem_recalc_inode(inode); |
| swap = shmem_get_swap(info, index); |
| if (swap.val) { |
| /* Look it up and read it in.. */ |
| page = lookup_swap_cache(swap); |
| if (!page) { |
| spin_unlock(&info->lock); |
| /* here we actually do the io */ |
| if (fault_type) |
| *fault_type |= VM_FAULT_MAJOR; |
| page = shmem_swapin(swap, gfp, info, index); |
| if (!page) { |
| swp_entry_t nswap = shmem_get_swap(info, index); |
| if (nswap.val == swap.val) { |
| error = -ENOMEM; |
| goto out; |
| } |
| goto repeat; |
| } |
| wait_on_page_locked(page); |
| page_cache_release(page); |
| goto repeat; |
| } |
| |
| /* We have to do this with page locked to prevent races */ |
| if (!trylock_page(page)) { |
| spin_unlock(&info->lock); |
| wait_on_page_locked(page); |
| page_cache_release(page); |
| goto repeat; |
| } |
| if (PageWriteback(page)) { |
| spin_unlock(&info->lock); |
| wait_on_page_writeback(page); |
| unlock_page(page); |
| page_cache_release(page); |
| goto repeat; |
| } |
| if (!PageUptodate(page)) { |
| spin_unlock(&info->lock); |
| unlock_page(page); |
| page_cache_release(page); |
| error = -EIO; |
| goto out; |
| } |
| |
| error = add_to_page_cache_locked(page, mapping, |
| index, GFP_NOWAIT); |
| if (error) { |
| spin_unlock(&info->lock); |
| if (error == -ENOMEM) { |
| /* |
| * reclaim from proper memory cgroup and |
| * call memcg's OOM if needed. |
| */ |
| error = mem_cgroup_shmem_charge_fallback( |
| page, current->mm, gfp); |
| if (error) { |
| unlock_page(page); |
| page_cache_release(page); |
| goto out; |
| } |
| } |
| unlock_page(page); |
| page_cache_release(page); |
| goto repeat; |
| } |
| |
| delete_from_swap_cache(page); |
| shmem_put_swap(info, index, (swp_entry_t){0}); |
| info->swapped--; |
| spin_unlock(&info->lock); |
| set_page_dirty(page); |
| swap_free(swap); |
| |
| } else if (sgp == SGP_READ) { |
| page = find_get_page(mapping, index); |
| if (page && !trylock_page(page)) { |
| spin_unlock(&info->lock); |
| wait_on_page_locked(page); |
| page_cache_release(page); |
| goto repeat; |
| } |
| spin_unlock(&info->lock); |
| |
| } else if (prealloc_page) { |
| sbinfo = SHMEM_SB(inode->i_sb); |
| if (sbinfo->max_blocks) { |
| if (percpu_counter_compare(&sbinfo->used_blocks, |
| sbinfo->max_blocks) >= 0 || |
| shmem_acct_block(info->flags)) |
| goto nospace; |
| percpu_counter_inc(&sbinfo->used_blocks); |
| inode->i_blocks += BLOCKS_PER_PAGE; |
| } else if (shmem_acct_block(info->flags)) |
| goto nospace; |
| |
| page = prealloc_page; |
| prealloc_page = NULL; |
| |
| swap = shmem_get_swap(info, index); |
| if (swap.val) |
| mem_cgroup_uncharge_cache_page(page); |
| else |
| error = add_to_page_cache_lru(page, mapping, |
| index, GFP_NOWAIT); |
| /* |
| * At add_to_page_cache_lru() failure, |
| * uncharge will be done automatically. |
| */ |
| if (swap.val || error) { |
| shmem_unacct_blocks(info->flags, 1); |
| shmem_free_blocks(inode, 1); |
| spin_unlock(&info->lock); |
| page_cache_release(page); |
| goto repeat; |
| } |
| |
| info->alloced++; |
| spin_unlock(&info->lock); |
| clear_highpage(page); |
| flush_dcache_page(page); |
| SetPageUptodate(page); |
| if (sgp == SGP_DIRTY) |
| set_page_dirty(page); |
| |
| } else { |
| spin_unlock(&info->lock); |
| error = -ENOMEM; |
| goto out; |
| } |
| done: |
| *pagep = page; |
| error = 0; |
| out: |
| if (prealloc_page) { |
| mem_cgroup_uncharge_cache_page(prealloc_page); |
| page_cache_release(prealloc_page); |
| } |
| return error; |
| |
| nospace: |
| /* |
| * Perhaps the page was brought in from swap between find_lock_page |
| * and taking info->lock? We allow for that at add_to_page_cache_lru, |
| * but must also avoid reporting a spurious ENOSPC while working on a |
| * full tmpfs. |
| */ |
| page = find_get_page(mapping, index); |
| spin_unlock(&info->lock); |
| if (page) { |
| page_cache_release(page); |
| goto repeat; |
| } |
| error = -ENOSPC; |
| goto out; |
| } |
| |
| static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| { |
| struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
| int error; |
| int ret = VM_FAULT_LOCKED; |
| |
| if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
| return VM_FAULT_SIGBUS; |
| |
| error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
| if (error) |
| return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); |
| |
| if (ret & VM_FAULT_MAJOR) { |
| count_vm_event(PGMAJFAULT); |
| mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); |
| } |
| return ret; |
| } |
| |
| #ifdef CONFIG_NUMA |
| static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
| { |
| struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
| return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); |
| } |
| |
| static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
| unsigned long addr) |
| { |
| struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
| pgoff_t index; |
| |
| index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
| return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); |
| } |
| #endif |
| |
| int shmem_lock(struct file *file, int lock, struct user_struct *user) |
| { |
| struct inode *inode = file->f_path.dentry->d_inode; |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| int retval = -ENOMEM; |
| |
| spin_lock(&info->lock); |
| if (lock && !(info->flags & VM_LOCKED)) { |
| if (!user_shm_lock(inode->i_size, user)) |
| goto out_nomem; |
| info->flags |= VM_LOCKED; |
| mapping_set_unevictable(file->f_mapping); |
| } |
| if (!lock && (info->flags & VM_LOCKED) && user) { |
| user_shm_unlock(inode->i_size, user); |
| info->flags &= ~VM_LOCKED; |
| mapping_clear_unevictable(file->f_mapping); |
| scan_mapping_unevictable_pages(file->f_mapping); |
| } |
| retval = 0; |
| |
| out_nomem: |
| spin_unlock(&info->lock); |
| return retval; |
| } |
| |
| static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| file_accessed(file); |
| vma->vm_ops = &shmem_vm_ops; |
| vma->vm_flags |= VM_CAN_NONLINEAR; |
| return 0; |
| } |
| |
| static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
| int mode, dev_t dev, unsigned long flags) |
| { |
| struct inode *inode; |
| struct shmem_inode_info *info; |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| |
| if (shmem_reserve_inode(sb)) |
| return NULL; |
| |
| inode = new_inode(sb); |
| if (inode) { |
| inode->i_ino = get_next_ino(); |
| inode_init_owner(inode, dir, mode); |
| inode->i_blocks = 0; |
| inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
| inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| inode->i_generation = get_seconds(); |
| info = SHMEM_I(inode); |
| memset(info, 0, (char *)inode - (char *)info); |
| spin_lock_init(&info->lock); |
| info->flags = flags & VM_NORESERVE; |
| INIT_LIST_HEAD(&info->swaplist); |
| INIT_LIST_HEAD(&info->xattr_list); |
| cache_no_acl(inode); |
| |
| switch (mode & S_IFMT) { |
| default: |
| inode->i_op = &shmem_special_inode_operations; |
| init_special_inode(inode, mode, dev); |
| break; |
| case S_IFREG: |
| inode->i_mapping->a_ops = &shmem_aops; |
| inode->i_op = &shmem_inode_operations; |
| inode->i_fop = &shmem_file_operations; |
| mpol_shared_policy_init(&info->policy, |
| shmem_get_sbmpol(sbinfo)); |
| break; |
| case S_IFDIR: |
| inc_nlink(inode); |
| /* Some things misbehave if size == 0 on a directory */ |
| inode->i_size = 2 * BOGO_DIRENT_SIZE; |
| inode->i_op = &shmem_dir_inode_operations; |
| inode->i_fop = &simple_dir_operations; |
| break; |
| case S_IFLNK: |
| /* |
| * Must not load anything in the rbtree, |
| * mpol_free_shared_policy will not be called. |
| */ |
| mpol_shared_policy_init(&info->policy, NULL); |
| break; |
| } |
| } else |
| shmem_free_inode(sb); |
| return inode; |
| } |
| |
| #ifdef CONFIG_TMPFS |
| static const struct inode_operations shmem_symlink_inode_operations; |
| static const struct inode_operations shmem_symlink_inline_operations; |
| |
| static int |
| shmem_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| struct inode *inode = mapping->host; |
| pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
| return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); |
| } |
| |
| static int |
| shmem_write_end(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, |
| struct page *page, void *fsdata) |
| { |
| struct inode *inode = mapping->host; |
| |
| if (pos + copied > inode->i_size) |
| i_size_write(inode, pos + copied); |
| |
| set_page_dirty(page); |
| unlock_page(page); |
| page_cache_release(page); |
| |
| return copied; |
| } |
| |
| static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
| { |
| struct inode *inode = filp->f_path.dentry->d_inode; |
| struct address_space *mapping = inode->i_mapping; |
| pgoff_t index; |
| unsigned long offset; |
| enum sgp_type sgp = SGP_READ; |
| |
| /* |
| * Might this read be for a stacking filesystem? Then when reading |
| * holes of a sparse file, we actually need to allocate those pages, |
| * and even mark them dirty, so it cannot exceed the max_blocks limit. |
| */ |
| if (segment_eq(get_fs(), KERNEL_DS)) |
| sgp = SGP_DIRTY; |
| |
| index = *ppos >> PAGE_CACHE_SHIFT; |
| offset = *ppos & ~PAGE_CACHE_MASK; |
| |
| for (;;) { |
| struct page *page = NULL; |
| pgoff_t end_index; |
| unsigned long nr, ret; |
| loff_t i_size = i_size_read(inode); |
| |
| end_index = i_size >> PAGE_CACHE_SHIFT; |
| if (index > end_index) |
| break; |
| if (index == end_index) { |
| nr = i_size & ~PAGE_CACHE_MASK; |
| if (nr <= offset) |
| break; |
| } |
| |
| desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
| if (desc->error) { |
| if (desc->error == -EINVAL) |
| desc->error = 0; |
| break; |
| } |
| if (page) |
| unlock_page(page); |
| |
| /* |
| * We must evaluate after, since reads (unlike writes) |
| * are called without i_mutex protection against truncate |
| */ |
| nr = PAGE_CACHE_SIZE; |
| i_size = i_size_read(inode); |
| end_index = i_size >> PAGE_CACHE_SHIFT; |
| if (index == end_index) { |
| nr = i_size & ~PAGE_CACHE_MASK; |
| if (nr <= offset) { |
| if (page) |
| page_cache_release(page); |
| break; |
| } |
| } |
| nr -= offset; |
| |
| if (page) { |
| /* |
| * If users can be writing to this page using arbitrary |
| * virtual addresses, take care about potential aliasing |
| * before reading the page on the kernel side. |
| */ |
| if (mapping_writably_mapped(mapping)) |
| flush_dcache_page(page); |
| /* |
| * Mark the page accessed if we read the beginning. |
| */ |
| if (!offset) |
| mark_page_accessed(page); |
| } else { |
| page = ZERO_PAGE(0); |
| page_cache_get(page); |
| } |
| |
| /* |
| * Ok, we have the page, and it's up-to-date, so |
| * now we can copy it to user space... |
| * |
| * The actor routine returns how many bytes were actually used.. |
| * NOTE! This may not be the same as how much of a user buffer |
| * we filled up (we may be padding etc), so we can only update |
| * "pos" here (the actor routine has to update the user buffer |
| * pointers and the remaining count). |
| */ |
| ret = actor(desc, page, offset, nr); |
| offset += ret; |
| index += offset >> PAGE_CACHE_SHIFT; |
| offset &= ~PAGE_CACHE_MASK; |
| |
| page_cache_release(page); |
| if (ret != nr || !desc->count) |
| break; |
| |
| cond_resched(); |
| } |
| |
| *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; |
| file_accessed(filp); |
| } |
| |
| static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
| const struct iovec *iov, unsigned long nr_segs, loff_t pos) |
| { |
| struct file *filp = iocb->ki_filp; |
| ssize_t retval; |
| unsigned long seg; |
| size_t count; |
| loff_t *ppos = &iocb->ki_pos; |
| |
| retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); |
| if (retval) |
| return retval; |
| |
| for (seg = 0; seg < nr_segs; seg++) { |
| read_descriptor_t desc; |
| |
| desc.written = 0; |
| desc.arg.buf = iov[seg].iov_base; |
| desc.count = iov[seg].iov_len; |
| if (desc.count == 0) |
| continue; |
| desc.error = 0; |
| do_shmem_file_read(filp, ppos, &desc, file_read_actor); |
| retval += desc.written; |
| if (desc.error) { |
| retval = retval ?: desc.error; |
| break; |
| } |
| if (desc.count > 0) |
| break; |
| } |
| return retval; |
| } |
| |
| static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, |
| struct pipe_inode_info *pipe, size_t len, |
| unsigned int flags) |
| { |
| struct address_space *mapping = in->f_mapping; |
| struct inode *inode = mapping->host; |
| unsigned int loff, nr_pages, req_pages; |
| struct page *pages[PIPE_DEF_BUFFERS]; |
| struct partial_page partial[PIPE_DEF_BUFFERS]; |
| struct page *page; |
| pgoff_t index, end_index; |
| loff_t isize, left; |
| int error, page_nr; |
| struct splice_pipe_desc spd = { |
| .pages = pages, |
| .partial = partial, |
| .flags = flags, |
| .ops = &page_cache_pipe_buf_ops, |
| .spd_release = spd_release_page, |
| }; |
| |
| isize = i_size_read(inode); |
| if (unlikely(*ppos >= isize)) |
| return 0; |
| |
| left = isize - *ppos; |
| if (unlikely(left < len)) |
| len = left; |
| |
| if (splice_grow_spd(pipe, &spd)) |
| return -ENOMEM; |
| |
| index = *ppos >> PAGE_CACHE_SHIFT; |
| loff = *ppos & ~PAGE_CACHE_MASK; |
| req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| nr_pages = min(req_pages, pipe->buffers); |
| |
| spd.nr_pages = find_get_pages_contig(mapping, index, |
| nr_pages, spd.pages); |
| index += spd.nr_pages; |
| error = 0; |
| |
| while (spd.nr_pages < nr_pages) { |
| error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); |
| if (error) |
| break; |
| unlock_page(page); |
| spd.pages[spd.nr_pages++] = page; |
| index++; |
| } |
| |
| index = *ppos >> PAGE_CACHE_SHIFT; |
| nr_pages = spd.nr_pages; |
| spd.nr_pages = 0; |
| |
| for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
| unsigned int this_len; |
| |
| if (!len) |
| break; |
| |
| this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
| page = spd.pages[page_nr]; |
| |
| if (!PageUptodate(page) || page->mapping != mapping) { |
| error = shmem_getpage(inode, index, &page, |
| SGP_CACHE, NULL); |
| if (error) |
| break; |
| unlock_page(page); |
| page_cache_release(spd.pages[page_nr]); |
| spd.pages[page_nr] = page; |
| } |
| |
| isize = i_size_read(inode); |
| end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
| if (unlikely(!isize || index > end_index)) |
| break; |
| |
| if (end_index == index) { |
| unsigned int plen; |
| |
| plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
| if (plen <= loff) |
| break; |
| |
| this_len = min(this_len, plen - loff); |
| len = this_len; |
| } |
| |
| spd.partial[page_nr].offset = loff; |
| spd.partial[page_nr].len = this_len; |
| len -= this_len; |
| loff = 0; |
| spd.nr_pages++; |
| index++; |
| } |
| |
| while (page_nr < nr_pages) |
| page_cache_release(spd.pages[page_nr++]); |
| |
| if (spd.nr_pages) |
| error = splice_to_pipe(pipe, &spd); |
| |
| splice_shrink_spd(pipe, &spd); |
| |
| if (error > 0) { |
| *ppos += error; |
| file_accessed(in); |
| } |
| return error; |
| } |
| |
| static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
| |
| buf->f_type = TMPFS_MAGIC; |
| buf->f_bsize = PAGE_CACHE_SIZE; |
| buf->f_namelen = NAME_MAX; |
| if (sbinfo->max_blocks) { |
| buf->f_blocks = sbinfo->max_blocks; |
| buf->f_bavail = |
| buf->f_bfree = sbinfo->max_blocks - |
| percpu_counter_sum(&sbinfo->used_blocks); |
| } |
| if (sbinfo->max_inodes) { |
| buf->f_files = sbinfo->max_inodes; |
| buf->f_ffree = sbinfo->free_inodes; |
| } |
| /* else leave those fields 0 like simple_statfs */ |
| return 0; |
| } |
| |
| /* |
| * File creation. Allocate an inode, and we're done.. |
| */ |
| static int |
| shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) |
| { |
| struct inode *inode; |
| int error = -ENOSPC; |
| |
| inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
| if (inode) { |
| error = security_inode_init_security(inode, dir, |
| &dentry->d_name, NULL, |
| NULL, NULL); |
| if (error) { |
| if (error != -EOPNOTSUPP) { |
| iput(inode); |
| return error; |
| } |
| } |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| error = generic_acl_init(inode, dir); |
| if (error) { |
| iput(inode); |
| return error; |
| } |
| #else |
| error = 0; |
| #endif |
| dir->i_size += BOGO_DIRENT_SIZE; |
| dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| d_instantiate(dentry, inode); |
| dget(dentry); /* Extra count - pin the dentry in core */ |
| } |
| return error; |
| } |
| |
| static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
| { |
| int error; |
| |
| if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) |
| return error; |
| inc_nlink(dir); |
| return 0; |
| } |
| |
| static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, |
| struct nameidata *nd) |
| { |
| return shmem_mknod(dir, dentry, mode | S_IFREG, 0); |
| } |
| |
| /* |
| * Link a file.. |
| */ |
| static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
| { |
| struct inode *inode = old_dentry->d_inode; |
| int ret; |
| |
| /* |
| * No ordinary (disk based) filesystem counts links as inodes; |
| * but each new link needs a new dentry, pinning lowmem, and |
| * tmpfs dentries cannot be pruned until they are unlinked. |
| */ |
| ret = shmem_reserve_inode(inode->i_sb); |
| if (ret) |
| goto out; |
| |
| dir->i_size += BOGO_DIRENT_SIZE; |
| inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| inc_nlink(inode); |
| ihold(inode); /* New dentry reference */ |
| dget(dentry); /* Extra pinning count for the created dentry */ |
| d_instantiate(dentry, inode); |
| out: |
| return ret; |
| } |
| |
| static int shmem_unlink(struct inode *dir, struct dentry *dentry) |
| { |
| struct inode *inode = dentry->d_inode; |
| |
| if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
| shmem_free_inode(inode->i_sb); |
| |
| dir->i_size -= BOGO_DIRENT_SIZE; |
| inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| drop_nlink(inode); |
| dput(dentry); /* Undo the count from "create" - this does all the work */ |
| return 0; |
| } |
| |
| static int shmem_rmdir(struct inode *dir, struct dentry *dentry) |
| { |
| if (!simple_empty(dentry)) |
| return -ENOTEMPTY; |
| |
| drop_nlink(dentry->d_inode); |
| drop_nlink(dir); |
| return shmem_unlink(dir, dentry); |
| } |
| |
| /* |
| * The VFS layer already does all the dentry stuff for rename, |
| * we just have to decrement the usage count for the target if |
| * it exists so that the VFS layer correctly free's it when it |
| * gets overwritten. |
| */ |
| static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) |
| { |
| struct inode *inode = old_dentry->d_inode; |
| int they_are_dirs = S_ISDIR(inode->i_mode); |
| |
| if (!simple_empty(new_dentry)) |
| return -ENOTEMPTY; |
| |
| if (new_dentry->d_inode) { |
| (void) shmem_unlink(new_dir, new_dentry); |
| if (they_are_dirs) |
| drop_nlink(old_dir); |
| } else if (they_are_dirs) { |
| drop_nlink(old_dir); |
| inc_nlink(new_dir); |
| } |
| |
| old_dir->i_size -= BOGO_DIRENT_SIZE; |
| new_dir->i_size += BOGO_DIRENT_SIZE; |
| old_dir->i_ctime = old_dir->i_mtime = |
| new_dir->i_ctime = new_dir->i_mtime = |
| inode->i_ctime = CURRENT_TIME; |
| return 0; |
| } |
| |
| static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) |
| { |
| int error; |
| int len; |
| struct inode *inode; |
| struct page *page; |
| char *kaddr; |
| struct shmem_inode_info *info; |
| |
| len = strlen(symname) + 1; |
| if (len > PAGE_CACHE_SIZE) |
| return -ENAMETOOLONG; |
| |
| inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
| if (!inode) |
| return -ENOSPC; |
| |
| error = security_inode_init_security(inode, dir, &dentry->d_name, NULL, |
| NULL, NULL); |
| if (error) { |
| if (error != -EOPNOTSUPP) { |
| iput(inode); |
| return error; |
| } |
| error = 0; |
| } |
| |
| info = SHMEM_I(inode); |
| inode->i_size = len-1; |
| if (len <= SHMEM_SYMLINK_INLINE_LEN) { |
| /* do it inline */ |
| memcpy(info->inline_symlink, symname, len); |
| inode->i_op = &shmem_symlink_inline_operations; |
| } else { |
| error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); |
| if (error) { |
| iput(inode); |
| return error; |
| } |
| inode->i_mapping->a_ops = &shmem_aops; |
| inode->i_op = &shmem_symlink_inode_operations; |
| kaddr = kmap_atomic(page, KM_USER0); |
| memcpy(kaddr, symname, len); |
| kunmap_atomic(kaddr, KM_USER0); |
| set_page_dirty(page); |
| unlock_page(page); |
| page_cache_release(page); |
| } |
| dir->i_size += BOGO_DIRENT_SIZE; |
| dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| d_instantiate(dentry, inode); |
| dget(dentry); |
| return 0; |
| } |
| |
| static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
| { |
| nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink); |
| return NULL; |
| } |
| |
| static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
| { |
| struct page *page = NULL; |
| int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
| nd_set_link(nd, error ? ERR_PTR(error) : kmap(page)); |
| if (page) |
| unlock_page(page); |
| return page; |
| } |
| |
| static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
| { |
| if (!IS_ERR(nd_get_link(nd))) { |
| struct page *page = cookie; |
| kunmap(page); |
| mark_page_accessed(page); |
| page_cache_release(page); |
| } |
| } |
| |
| #ifdef CONFIG_TMPFS_XATTR |
| /* |
| * Superblocks without xattr inode operations may get some security.* xattr |
| * support from the LSM "for free". As soon as we have any other xattrs |
| * like ACLs, we also need to implement the security.* handlers at |
| * filesystem level, though. |
| */ |
| |
| static int shmem_xattr_get(struct dentry *dentry, const char *name, |
| void *buffer, size_t size) |
| { |
| struct shmem_inode_info *info; |
| struct shmem_xattr *xattr; |
| int ret = -ENODATA; |
| |
| info = SHMEM_I(dentry->d_inode); |
| |
| spin_lock(&info->lock); |
| list_for_each_entry(xattr, &info->xattr_list, list) { |
| if (strcmp(name, xattr->name)) |
| continue; |
| |
| ret = xattr->size; |
| if (buffer) { |
| if (size < xattr->size) |
| ret = -ERANGE; |
| else |
| memcpy(buffer, xattr->value, xattr->size); |
| } |
| break; |
| } |
| spin_unlock(&info->lock); |
| return ret; |
| } |
| |
| static int shmem_xattr_set(struct dentry *dentry, const char *name, |
| const void *value, size_t size, int flags) |
| { |
| struct inode *inode = dentry->d_inode; |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_xattr *xattr; |
| struct shmem_xattr *new_xattr = NULL; |
| size_t len; |
| int err = 0; |
| |
| /* value == NULL means remove */ |
| if (value) { |
| /* wrap around? */ |
| len = sizeof(*new_xattr) + size; |
| if (len <= sizeof(*new_xattr)) |
| return -ENOMEM; |
| |
| new_xattr = kmalloc(len, GFP_KERNEL); |
| if (!new_xattr) |
| return -ENOMEM; |
| |
| new_xattr->name = kstrdup(name, GFP_KERNEL); |
| if (!new_xattr->name) { |
| kfree(new_xattr); |
| return -ENOMEM; |
| } |
| |
| new_xattr->size = size; |
| memcpy(new_xattr->value, value, size); |
| } |
| |
| spin_lock(&info->lock); |
| list_for_each_entry(xattr, &info->xattr_list, list) { |
| if (!strcmp(name, xattr->name)) { |
| if (flags & XATTR_CREATE) { |
| xattr = new_xattr; |
| err = -EEXIST; |
| } else if (new_xattr) { |
| list_replace(&xattr->list, &new_xattr->list); |
| } else { |
| list_del(&xattr->list); |
| } |
| goto out; |
| } |
| } |
| if (flags & XATTR_REPLACE) { |
| xattr = new_xattr; |
| err = -ENODATA; |
| } else { |
| list_add(&new_xattr->list, &info->xattr_list); |
| xattr = NULL; |
| } |
| out: |
| spin_unlock(&info->lock); |
| if (xattr) |
| kfree(xattr->name); |
| kfree(xattr); |
| return err; |
| } |
| |
| static const struct xattr_handler *shmem_xattr_handlers[] = { |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| &generic_acl_access_handler, |
| &generic_acl_default_handler, |
| #endif |
| NULL |
| }; |
| |
| static int shmem_xattr_validate(const char *name) |
| { |
| struct { const char *prefix; size_t len; } arr[] = { |
| { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, |
| { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } |
| }; |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(arr); i++) { |
| size_t preflen = arr[i].len; |
| if (strncmp(name, arr[i].prefix, preflen) == 0) { |
| if (!name[preflen]) |
| return -EINVAL; |
| return 0; |
| } |
| } |
| return -EOPNOTSUPP; |
| } |
| |
| static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, |
| void *buffer, size_t size) |
| { |
| int err; |
| |
| /* |
| * If this is a request for a synthetic attribute in the system.* |
| * namespace use the generic infrastructure to resolve a handler |
| * for it via sb->s_xattr. |
| */ |
| if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
| return generic_getxattr(dentry, name, buffer, size); |
| |
| err = shmem_xattr_validate(name); |
| if (err) |
| return err; |
| |
| return shmem_xattr_get(dentry, name, buffer, size); |
| } |
| |
| static int shmem_setxattr(struct dentry *dentry, const char *name, |
| const void *value, size_t size, int flags) |
| { |
| int err; |
| |
| /* |
| * If this is a request for a synthetic attribute in the system.* |
| * namespace use the generic infrastructure to resolve a handler |
| * for it via sb->s_xattr. |
| */ |
| if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
| return generic_setxattr(dentry, name, value, size, flags); |
| |
| err = shmem_xattr_validate(name); |
| if (err) |
| return err; |
| |
| if (size == 0) |
| value = ""; /* empty EA, do not remove */ |
| |
| return shmem_xattr_set(dentry, name, value, size, flags); |
| |
| } |
| |
| static int shmem_removexattr(struct dentry *dentry, const char *name) |
| { |
| int err; |
| |
| /* |
| * If this is a request for a synthetic attribute in the system.* |
| * namespace use the generic infrastructure to resolve a handler |
| * for it via sb->s_xattr. |
| */ |
| if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
| return generic_removexattr(dentry, name); |
| |
| err = shmem_xattr_validate(name); |
| if (err) |
| return err; |
| |
| return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE); |
| } |
| |
| static bool xattr_is_trusted(const char *name) |
| { |
| return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); |
| } |
| |
| static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) |
| { |
| bool trusted = capable(CAP_SYS_ADMIN); |
| struct shmem_xattr *xattr; |
| struct shmem_inode_info *info; |
| size_t used = 0; |
| |
| info = SHMEM_I(dentry->d_inode); |
| |
| spin_lock(&info->lock); |
| list_for_each_entry(xattr, &info->xattr_list, list) { |
| size_t len; |
| |
| /* skip "trusted." attributes for unprivileged callers */ |
| if (!trusted && xattr_is_trusted(xattr->name)) |
| continue; |
| |
| len = strlen(xattr->name) + 1; |
| used += len; |
| if (buffer) { |
| if (size < used) { |
| used = -ERANGE; |
| break; |
| } |
| memcpy(buffer, xattr->name, len); |
| buffer += len; |
| } |
| } |
| spin_unlock(&info->lock); |
| |
| return used; |
| } |
| #endif /* CONFIG_TMPFS_XATTR */ |
| |
| static const struct inode_operations shmem_symlink_inline_operations = { |
| .readlink = generic_readlink, |
| .follow_link = shmem_follow_link_inline, |
| #ifdef CONFIG_TMPFS_XATTR |
| .setxattr = shmem_setxattr, |
| .getxattr = shmem_getxattr, |
| .listxattr = shmem_listxattr, |
| .removexattr = shmem_removexattr, |
| #endif |
| }; |
| |
| static const struct inode_operations shmem_symlink_inode_operations = { |
| .readlink = generic_readlink, |
| .follow_link = shmem_follow_link, |
| .put_link = shmem_put_link, |
| #ifdef CONFIG_TMPFS_XATTR |
| .setxattr = shmem_setxattr, |
| .getxattr = shmem_getxattr, |
| .listxattr = shmem_listxattr, |
| .removexattr = shmem_removexattr, |
| #endif |
| }; |
| |
| static struct dentry *shmem_get_parent(struct dentry *child) |
| { |
| return ERR_PTR(-ESTALE); |
| } |
| |
| static int shmem_match(struct inode *ino, void *vfh) |
| { |
| __u32 *fh = vfh; |
| __u64 inum = fh[2]; |
| inum = (inum << 32) | fh[1]; |
| return ino->i_ino == inum && fh[0] == ino->i_generation; |
| } |
| |
| static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
| struct fid *fid, int fh_len, int fh_type) |
| { |
| struct inode *inode; |
| struct dentry *dentry = NULL; |
| u64 inum = fid->raw[2]; |
| inum = (inum << 32) | fid->raw[1]; |
| |
| if (fh_len < 3) |
| return NULL; |
| |
| inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
| shmem_match, fid->raw); |
| if (inode) { |
| dentry = d_find_alias(inode); |
| iput(inode); |
| } |
| |
| return dentry; |
| } |
| |
| static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, |
| int connectable) |
| { |
| struct inode *inode = dentry->d_inode; |
| |
| if (*len < 3) { |
| *len = 3; |
| return 255; |
| } |
| |
| if (inode_unhashed(inode)) { |
| /* Unfortunately insert_inode_hash is not idempotent, |
| * so as we hash inodes here rather than at creation |
| * time, we need a lock to ensure we only try |
| * to do it once |
| */ |
| static DEFINE_SPINLOCK(lock); |
| spin_lock(&lock); |
| if (inode_unhashed(inode)) |
| __insert_inode_hash(inode, |
| inode->i_ino + inode->i_generation); |
| spin_unlock(&lock); |
| } |
| |
| fh[0] = inode->i_generation; |
| fh[1] = inode->i_ino; |
| fh[2] = ((__u64)inode->i_ino) >> 32; |
| |
| *len = 3; |
| return 1; |
| } |
| |
| static const struct export_operations shmem_export_ops = { |
| .get_parent = shmem_get_parent, |
| .encode_fh = shmem_encode_fh, |
| .fh_to_dentry = shmem_fh_to_dentry, |
| }; |
| |
| static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
| bool remount) |
| { |
| char *this_char, *value, *rest; |
| |
| while (options != NULL) { |
| this_char = options; |
| for (;;) { |
| /* |
| * NUL-terminate this option: unfortunately, |
| * mount options form a comma-separated list, |
| * but mpol's nodelist may also contain commas. |
| */ |
| options = strchr(options, ','); |
| if (options == NULL) |
| break; |
| options++; |
| if (!isdigit(*options)) { |
| options[-1] = '\0'; |
| break; |
| } |
| } |
| if (!*this_char) |
| continue; |
| if ((value = strchr(this_char,'=')) != NULL) { |
| *value++ = 0; |
| } else { |
| printk(KERN_ERR |
| "tmpfs: No value for mount option '%s'\n", |
| this_char); |
| return 1; |
| } |
| |
| if (!strcmp(this_char,"size")) { |
| unsigned long long size; |
| size = memparse(value,&rest); |
| if (*rest == '%') { |
| size <<= PAGE_SHIFT; |
| size *= totalram_pages; |
| do_div(size, 100); |
| rest++; |
| } |
| if (*rest) |
| goto bad_val; |
| sbinfo->max_blocks = |
| DIV_ROUND_UP(size, PAGE_CACHE_SIZE); |
| } else if (!strcmp(this_char,"nr_blocks")) { |
| sbinfo->max_blocks = memparse(value, &rest); |
| if (*rest) |
| goto bad_val; |
| } else if (!strcmp(this_char,"nr_inodes")) { |
| sbinfo->max_inodes = memparse(value, &rest); |
| if (*rest) |
| goto bad_val; |
| } else if (!strcmp(this_char,"mode")) { |
| if (remount) |
| continue; |
| sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
| if (*rest) |
| goto bad_val; |
| } else if (!strcmp(this_char,"uid")) { |
| if (remount) |
| continue; |
| sbinfo->uid = simple_strtoul(value, &rest, 0); |
| if (*rest) |
| goto bad_val; |
| } else if (!strcmp(this_char,"gid")) { |
| if (remount) |
| continue; |
| sbinfo->gid = simple_strtoul(value, &rest, 0); |
| if (*rest) |
| goto bad_val; |
| } else if (!strcmp(this_char,"mpol")) { |
| if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
| goto bad_val; |
| } else { |
| printk(KERN_ERR "tmpfs: Bad mount option %s\n", |
| this_char); |
| return 1; |
| } |
| } |
| return 0; |
| |
| bad_val: |
| printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", |
| value, this_char); |
| return 1; |
| |
| } |
| |
| static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| struct shmem_sb_info config = *sbinfo; |
| unsigned long inodes; |
| int error = -EINVAL; |
| |
| if (shmem_parse_options(data, &config, true)) |
| return error; |
| |
| spin_lock(&sbinfo->stat_lock); |
| inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
| if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
| goto out; |
| if (config.max_inodes < inodes) |
| goto out; |
| /* |
| * Those tests also disallow limited->unlimited while any are in |
| * use, so i_blocks will always be zero when max_blocks is zero; |
| * but we must separately disallow unlimited->limited, because |
| * in that case we have no record of how much is already in use. |
| */ |
| if (config.max_blocks && !sbinfo->max_blocks) |
| goto out; |
| if (config.max_inodes && !sbinfo->max_inodes) |
| goto out; |
| |
| error = 0; |
| sbinfo->max_blocks = config.max_blocks; |
| sbinfo->max_inodes = config.max_inodes; |
| sbinfo->free_inodes = config.max_inodes - inodes; |
| |
| mpol_put(sbinfo->mpol); |
| sbinfo->mpol = config.mpol; /* transfers initial ref */ |
| out: |
| spin_unlock(&sbinfo->stat_lock); |
| return error; |
| } |
| |
| static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); |
| |
| if (sbinfo->max_blocks != shmem_default_max_blocks()) |
| seq_printf(seq, ",size=%luk", |
| sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); |
| if (sbinfo->max_inodes != shmem_default_max_inodes()) |
| seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); |
| if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) |
| seq_printf(seq, ",mode=%03o", sbinfo->mode); |
| if (sbinfo->uid != 0) |
| seq_printf(seq, ",uid=%u", sbinfo->uid); |
| if (sbinfo->gid != 0) |
| seq_printf(seq, ",gid=%u", sbinfo->gid); |
| shmem_show_mpol(seq, sbinfo->mpol); |
| return 0; |
| } |
| #endif /* CONFIG_TMPFS */ |
| |
| static void shmem_put_super(struct super_block *sb) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| |
| percpu_counter_destroy(&sbinfo->used_blocks); |
| kfree(sbinfo); |
| sb->s_fs_info = NULL; |
| } |
| |
| int shmem_fill_super(struct super_block *sb, void *data, int silent) |
| { |
| struct inode *inode; |
| struct dentry *root; |
| struct shmem_sb_info *sbinfo; |
| int err = -ENOMEM; |
| |
| /* Round up to L1_CACHE_BYTES to resist false sharing */ |
| sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
| L1_CACHE_BYTES), GFP_KERNEL); |
| if (!sbinfo) |
| return -ENOMEM; |
| |
| sbinfo->mode = S_IRWXUGO | S_ISVTX; |
| sbinfo->uid = current_fsuid(); |
| sbinfo->gid = current_fsgid(); |
| sb->s_fs_info = sbinfo; |
| |
| #ifdef CONFIG_TMPFS |
| /* |
| * Per default we only allow half of the physical ram per |
| * tmpfs instance, limiting inodes to one per page of lowmem; |
| * but the internal instance is left unlimited. |
| */ |
| if (!(sb->s_flags & MS_NOUSER)) { |
| sbinfo->max_blocks = shmem_default_max_blocks(); |
| sbinfo->max_inodes = shmem_default_max_inodes(); |
| if (shmem_parse_options(data, sbinfo, false)) { |
| err = -EINVAL; |
| goto failed; |
| } |
| } |
| sb->s_export_op = &shmem_export_ops; |
| #else |
| sb->s_flags |= MS_NOUSER; |
| #endif |
| |
| spin_lock_init(&sbinfo->stat_lock); |
| if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
| goto failed; |
| sbinfo->free_inodes = sbinfo->max_inodes; |
| |
| sb->s_maxbytes = MAX_LFS_FILESIZE; |
| sb->s_blocksize = PAGE_CACHE_SIZE; |
| sb->s_blocksize_bits = PAGE_CACHE_SHIFT; |
| sb->s_magic = TMPFS_MAGIC; |
| sb->s_op = &shmem_ops; |
| sb->s_time_gran = 1; |
| #ifdef CONFIG_TMPFS_XATTR |
| sb->s_xattr = shmem_xattr_handlers; |
| #endif |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| sb->s_flags |= MS_POSIXACL; |
| #endif |
| |
| inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
| if (!inode) |
| goto failed; |
| inode->i_uid = sbinfo->uid; |
| inode->i_gid = sbinfo->gid; |
| root = d_alloc_root(inode); |
| if (!root) |
| goto failed_iput; |
| sb->s_root = root; |
| return 0; |
| |
| failed_iput: |
| iput(inode); |
| failed: |
| shmem_put_super(sb); |
| return err; |
| } |
| |
| static struct kmem_cache *shmem_inode_cachep; |
| |
| static struct inode *shmem_alloc_inode(struct super_block *sb) |
| { |
| struct shmem_inode_info *info; |
| info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
| if (!info) |
| return NULL; |
| return &info->vfs_inode; |
| } |
| |
| static void shmem_destroy_callback(struct rcu_head *head) |
| { |
| struct inode *inode = container_of(head, struct inode, i_rcu); |
| INIT_LIST_HEAD(&inode->i_dentry); |
| kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
| } |
| |
| static void shmem_destroy_inode(struct inode *inode) |
| { |
| if ((inode->i_mode & S_IFMT) == S_IFREG) { |
| /* only struct inode is valid if it's an inline symlink */ |
| mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
| } |
| call_rcu(&inode->i_rcu, shmem_destroy_callback); |
| } |
| |
| static void shmem_init_inode(void *foo) |
| { |
| struct shmem_inode_info *info = foo; |
| inode_init_once(&info->vfs_inode); |
| } |
| |
| static int shmem_init_inodecache(void) |
| { |
| shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", |
| sizeof(struct shmem_inode_info), |
| 0, SLAB_PANIC, shmem_init_inode); |
| return 0; |
| } |
| |
| static void shmem_destroy_inodecache(void) |
| { |
| kmem_cache_destroy(shmem_inode_cachep); |
| } |
| |
| static const struct address_space_operations shmem_aops = { |
| .writepage = shmem_writepage, |
| .set_page_dirty = __set_page_dirty_no_writeback, |
| #ifdef CONFIG_TMPFS |
| .write_begin = shmem_write_begin, |
| .write_end = shmem_write_end, |
| #endif |
| .migratepage = migrate_page, |
| .error_remove_page = generic_error_remove_page, |
| }; |
| |
| static const struct file_operations shmem_file_operations = { |
| .mmap = shmem_mmap, |
| #ifdef CONFIG_TMPFS |
| .llseek = generic_file_llseek, |
| .read = do_sync_read, |
| .write = do_sync_write, |
| .aio_read = shmem_file_aio_read, |
| .aio_write = generic_file_aio_write, |
| .fsync = noop_fsync, |
| .splice_read = shmem_file_splice_read, |
| .splice_write = generic_file_splice_write, |
| #endif |
| }; |
| |
| static const struct inode_operations shmem_inode_operations = { |
| .setattr = shmem_setattr, |
| .truncate_range = shmem_truncate_range, |
| #ifdef CONFIG_TMPFS_XATTR |
| .setxattr = shmem_setxattr, |
| .getxattr = shmem_getxattr, |
| .listxattr = shmem_listxattr, |
| .removexattr = shmem_removexattr, |
| #endif |
| }; |
| |
| static const struct inode_operations shmem_dir_inode_operations = { |
| #ifdef CONFIG_TMPFS |
| .create = shmem_create, |
| .lookup = simple_lookup, |
| .link = shmem_link, |
| .unlink = shmem_unlink, |
| .symlink = shmem_symlink, |
| .mkdir = shmem_mkdir, |
| .rmdir = shmem_rmdir, |
| .mknod = shmem_mknod, |
| .rename = shmem_rename, |
| #endif |
| #ifdef CONFIG_TMPFS_XATTR |
| .setxattr = shmem_setxattr, |
| .getxattr = shmem_getxattr, |
| .listxattr = shmem_listxattr, |
| .removexattr = shmem_removexattr, |
| #endif |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| .setattr = shmem_setattr, |
| #endif |
| }; |
| |
| static const struct inode_operations shmem_special_inode_operations = { |
| #ifdef CONFIG_TMPFS_XATTR |
| .setxattr = shmem_setxattr, |
| .getxattr = shmem_getxattr, |
| .listxattr = shmem_listxattr, |
| .removexattr = shmem_removexattr, |
| #endif |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| .setattr = shmem_setattr, |
| #endif |
| }; |
| |
| static const struct super_operations shmem_ops = { |
| .alloc_inode = shmem_alloc_inode, |
| .destroy_inode = shmem_destroy_inode, |
| #ifdef CONFIG_TMPFS |
| .statfs = shmem_statfs, |
| .remount_fs = shmem_remount_fs, |
| .show_options = shmem_show_options, |
| #endif |
| .evict_inode = shmem_evict_inode, |
| .drop_inode = generic_delete_inode, |
| .put_super = shmem_put_super, |
| }; |
| |
| static const struct vm_operations_struct shmem_vm_ops = { |
| .fault = shmem_fault, |
| #ifdef CONFIG_NUMA |
| .set_policy = shmem_set_policy, |
| .get_policy = shmem_get_policy, |
| #endif |
| }; |
| |
| static struct dentry *shmem_mount(struct file_system_type *fs_type, |
| int flags, const char *dev_name, void *data) |
| { |
| return mount_nodev(fs_type, flags, data, shmem_fill_super); |
| } |
| |
| static struct file_system_type shmem_fs_type = { |
| .owner = THIS_MODULE, |
| .name = "tmpfs", |
| .mount = shmem_mount, |
| .kill_sb = kill_litter_super, |
| }; |
| |
| int __init shmem_init(void) |
| { |
| int error; |
| |
| error = bdi_init(&shmem_backing_dev_info); |
| if (error) |
| goto out4; |
| |
| error = shmem_init_inodecache(); |
| if (error) |
| goto out3; |
| |
| error = register_filesystem(&shmem_fs_type); |
| if (error) { |
| printk(KERN_ERR "Could not register tmpfs\n"); |
| goto out2; |
| } |
| |
| shm_mnt = vfs_kern_mount(&shmem_fs_type, MS_NOUSER, |
| shmem_fs_type.name, NULL); |
| if (IS_ERR(shm_mnt)) { |
| error = PTR_ERR(shm_mnt); |
| printk(KERN_ERR "Could not kern_mount tmpfs\n"); |
| goto out1; |
| } |
| return 0; |
| |
| out1: |
| unregister_filesystem(&shmem_fs_type); |
| out2: |
| shmem_destroy_inodecache(); |
| out3: |
| bdi_destroy(&shmem_backing_dev_info); |
| out4: |
| shm_mnt = ERR_PTR(error); |
| return error; |
| } |
| |
| #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
| /** |
| * mem_cgroup_get_shmem_target - find page or swap assigned to the shmem file |
| * @inode: the inode to be searched |
| * @index: the page offset to be searched |
| * @pagep: the pointer for the found page to be stored |
| * @swapp: the pointer for the found swap entry to be stored |
| * |
| * If a page is found, refcount of it is incremented. Callers should handle |
| * these refcount. |
| */ |
| void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t index, |
| struct page **pagep, swp_entry_t *swapp) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct page *page = NULL; |
| swp_entry_t swap = {0}; |
| |
| if ((index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
| goto out; |
| |
| spin_lock(&info->lock); |
| #ifdef CONFIG_SWAP |
| swap = shmem_get_swap(info, index); |
| if (swap.val) |
| page = find_get_page(&swapper_space, swap.val); |
| else |
| #endif |
| page = find_get_page(inode->i_mapping, index); |
| spin_unlock(&info->lock); |
| out: |
| *pagep = page; |
| *swapp = swap; |
| } |
| #endif |
| |
| #else /* !CONFIG_SHMEM */ |
| |
| /* |
| * tiny-shmem: simple shmemfs and tmpfs using ramfs code |
| * |
| * This is intended for small system where the benefits of the full |
| * shmem code (swap-backed and resource-limited) are outweighed by |
| * their complexity. On systems without swap this code should be |
| * effectively equivalent, but much lighter weight. |
| */ |
| |
| #include <linux/ramfs.h> |
| |
| static struct file_system_type shmem_fs_type = { |
| .name = "tmpfs", |
| .mount = ramfs_mount, |
| .kill_sb = kill_litter_super, |
| }; |
| |
| int __init shmem_init(void) |
| { |
| BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
| |
| shm_mnt = kern_mount(&shmem_fs_type); |
| BUG_ON(IS_ERR(shm_mnt)); |
| |
| return 0; |
| } |
| |
| int shmem_unuse(swp_entry_t swap, struct page *page) |
| { |
| return 0; |
| } |
| |
| int shmem_lock(struct file *file, int lock, struct user_struct *user) |
| { |
| return 0; |
| } |
| |
| void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
| { |
| truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
| } |
| EXPORT_SYMBOL_GPL(shmem_truncate_range); |
| |
| #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
| /** |
| * mem_cgroup_get_shmem_target - find page or swap assigned to the shmem file |
| * @inode: the inode to be searched |
| * @index: the page offset to be searched |
| * @pagep: the pointer for the found page to be stored |
| * @swapp: the pointer for the found swap entry to be stored |
| * |
| * If a page is found, refcount of it is incremented. Callers should handle |
| * these refcount. |
| */ |
| void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t index, |
| struct page **pagep, swp_entry_t *swapp) |
| { |
| struct page *page = NULL; |
| |
| if ((index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
| goto out; |
| page = find_get_page(inode->i_mapping, index); |
| out: |
| *pagep = page; |
| *swapp = (swp_entry_t){0}; |
| } |
| #endif |
| |
| #define shmem_vm_ops generic_file_vm_ops |
| #define shmem_file_operations ramfs_file_operations |
| #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
| #define shmem_acct_size(flags, size) 0 |
| #define shmem_unacct_size(flags, size) do {} while (0) |
| |
| #endif /* CONFIG_SHMEM */ |
| |
| /* common code */ |
| |
| /** |
| * shmem_file_setup - get an unlinked file living in tmpfs |
| * @name: name for dentry (to be seen in /proc/<pid>/maps |
| * @size: size to be set for the file |
| * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
| */ |
| struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
| { |
| int error; |
| struct file *file; |
| struct inode *inode; |
| struct path path; |
| struct dentry *root; |
| struct qstr this; |
| |
| if (IS_ERR(shm_mnt)) |
| return (void *)shm_mnt; |
| |
| if (size < 0 || size > MAX_LFS_FILESIZE) |
| return ERR_PTR(-EINVAL); |
| |
| if (shmem_acct_size(flags, size)) |
| return ERR_PTR(-ENOMEM); |
| |
| error = -ENOMEM; |
| this.name = name; |
| this.len = strlen(name); |
| this.hash = 0; /* will go */ |
| root = shm_mnt->mnt_root; |
| path.dentry = d_alloc(root, &this); |
| if (!path.dentry) |
| goto put_memory; |
| path.mnt = mntget(shm_mnt); |
| |
| error = -ENOSPC; |
| inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
| if (!inode) |
| goto put_dentry; |
| |
| d_instantiate(path.dentry, inode); |
| inode->i_size = size; |
| inode->i_nlink = 0; /* It is unlinked */ |
| #ifndef CONFIG_MMU |
| error = ramfs_nommu_expand_for_mapping(inode, size); |
| if (error) |
| goto put_dentry; |
| #endif |
| |
| error = -ENFILE; |
| file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
| &shmem_file_operations); |
| if (!file) |
| goto put_dentry; |
| |
| return file; |
| |
| put_dentry: |
| path_put(&path); |
| put_memory: |
| shmem_unacct_size(flags, size); |
| return ERR_PTR(error); |
| } |
| EXPORT_SYMBOL_GPL(shmem_file_setup); |
| |
| /** |
| * shmem_zero_setup - setup a shared anonymous mapping |
| * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
| */ |
| int shmem_zero_setup(struct vm_area_struct *vma) |
| { |
| struct file *file; |
| loff_t size = vma->vm_end - vma->vm_start; |
| |
| file = shmem_file_setup("dev/zero", size, vma->vm_flags); |
| if (IS_ERR(file)) |
| return PTR_ERR(file); |
| |
| if (vma->vm_file) |
| fput(vma->vm_file); |
| vma->vm_file = file; |
| vma->vm_ops = &shmem_vm_ops; |
| vma->vm_flags |= VM_CAN_NONLINEAR; |
| return 0; |
| } |
| |
| /** |
| * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. |
| * @mapping: the page's address_space |
| * @index: the page index |
| * @gfp: the page allocator flags to use if allocating |
| * |
| * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", |
| * with any new page allocations done using the specified allocation flags. |
| * But read_cache_page_gfp() uses the ->readpage() method: which does not |
| * suit tmpfs, since it may have pages in swapcache, and needs to find those |
| * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. |
| * |
| * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
| * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. |
| */ |
| struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, |
| pgoff_t index, gfp_t gfp) |
| { |
| #ifdef CONFIG_SHMEM |
| struct inode *inode = mapping->host; |
| struct page *page; |
| int error; |
| |
| BUG_ON(mapping->a_ops != &shmem_aops); |
| error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); |
| if (error) |
| page = ERR_PTR(error); |
| else |
| unlock_page(page); |
| return page; |
| #else |
| /* |
| * The tiny !SHMEM case uses ramfs without swap |
| */ |
| return read_cache_page_gfp(mapping, index, gfp); |
| #endif |
| } |
| EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |